1. Let "D" and "O" be the demand and supply of a certain good, and P be the price of the same. If the supply (O) and demand (D) functions are represented as follows: O = 50P - 300 \quad D = 150 - 10P a) Calculate the equilibrium price of said good and explain what would happen if the price were higher and if it were lower than $5; $10 respectively. b) Calculate the demand and supply for each of the prices previously analyzed.

1 answer

To find the equilibrium price, we need to set the supply \( O \) equal to the demand \( D \). The given functions are:

\[ O = 50P - 300 \] \[ D = 150 - 10P \]

a) Calculate the equilibrium price.

To find equilibrium, set \( O \) equal to \( D \):

\[ 50P - 300 = 150 - 10P \]

Now, let's solve for \( P \):

  1. Add \( 10P \) to both sides:

\[ 50P + 10P - 300 = 150 \]

\[ 60P - 300 = 150 \]

  1. Add \( 300 \) to both sides:

\[ 60P = 450 \]

  1. Divide by \( 60 \):

\[ P = \frac{450}{60} = 7.5 \]

Thus, the equilibrium price \( P^* = 7.5 \).

What happens if the price is higher or lower than $7.5:

  • If the price is higher than $7.5 (for example, at \( P = 10 \)):

    • Calculate supply:

    \[ O = 50(10) - 300 = 500 - 300 = 200 \]

    • Calculate demand:

    \[ D = 150 - 10(10) = 150 - 100 = 50 \]

    • In this case, supply (200) exceeds demand (50), leading to a surplus of goods. Producers will lower their prices to clear this surplus, moving the price down toward equilibrium.
  • If the price is lower than $7.5 (for example, at \( P = 5 \)):

    • Calculate supply:

    \[ O = 50(5) - 300 = 250 - 300 = -50 \] (indicating no supply)

    • Calculate demand:

    \[ D = 150 - 10(5) = 150 - 50 = 100 \]

    • In this case, demand (100) exceeds supply (0), indicating a shortage of goods. Consumers will compete for the limited supply, driving the price up toward equilibrium.

b) Calculate the demand and supply for the prices of $5 and $10.

At \( P = 5 \):

  • Supply:

\[ O = 50(5) - 300 = 250 - 300 = -50 \quad \text{(no supply)} \]

  • Demand:

\[ D = 150 - 10(5) = 150 - 50 = 100 \]

At \( P = 10 \):

  • Supply:

\[ O = 50(10) - 300 = 500 - 300 = 200 \]

  • Demand:

\[ D = 150 - 10(10) = 150 - 100 = 50 \]

Summary of Results:

  • At \( P = 5 \):

    • Supply = 0 (no supply)
    • Demand = 100
  • At \( P = 10 \):

    • Supply = 200
    • Demand = 50

The equilibrium price is \( P = 7.5 \), with implications of surplus at higher prices and shortages at lower prices.